Organic element for electroluminescent devices
View Patent ↗Disclosed is an OLED device comprising a light-emitting layer (LEL) containing a host and a dopant located between a cathode and an anode wherein the emitter is an orange-red light emitting rubrene derivative represented by formula (II): wherein: a) there are identical branched alkyl or non-aromatic carbocyclic groups at the 2- and 8-positions; b) the phenyl rings in the 5- and 11-positions contain only para-substituents identical to the branched alkyl or non-aromatic carbocyclic groups in paragraph a); and c) the phenyl rings in the 6- and 12-positions are substituted.
1. An OLED device comprising a light-emitting layer (LEL) containing a host and an emitting dopant located between a cathode and an anode wherein the dopant is an orange-red light emitting rubrene derivative represented by formula (I):
wherein:
a) there are identical branched alkyl or non-aromatic carbocyclic groups at the 2- and 8-positions;
b) the phenyl rings in the 5- and 11-positions contain only para-substituents identical to the branched alkyl or non-aromatic carbocyclic groups in paragraph a); and
c) the phenyl rings in the 6- and 12-positions are substituted or not;
provided that all of the substituents are selected so that the wavelength of maximum emission (λ max ) in ethyl acetate is such that 563 nm<λ max ≦650 nm.
2. The device of claim 1 comprising a further light-emitting compound to provide a white light emission.
3. The device of claim 2 further comprising a blue light-emitting compound to provide a white light emission.
4. The device of claim 2 further comprising a filter over-lying the device.
5. The device of claim 2 wherein the layer comprises a host and dopant where the dopant is present in an amount of up to 10%-wt of the host.
6. The device of claim 5 wherein the dopant is present in an amount of 0.1–5.0%-wt of the host.
7. The device of claim 1 wherein the dopant is represented by formula (II):
wherein
R 1 is represented by the formula;
wherein each of R 3 , R 4 and R 5 is hydrogen or an independently selected substituent with no more than one being hydrogen or R 3 , R 4 and R 5 taken together can form a mono- or multi-cyclic ring system;
R 2 is a substituent group;
n is 1–5;
provided that all R 1 groups are the same; and
provided further, that the R 2 groups, their location and n value on one ring are the same as those on the second ring.
8. The device of claim 1 wherein the dopant is represented by formula (III):
wherein
R 2 is a substituent group;
n is 1–5; and
provided that the R 2 groups, their location and n value on one ring are the same as those on the second ring.
9. The device of claim 1 wherein the dopant is represented by formula (IV):
wherein
W represents the atoms necessary to complete a non-aromatic carbocyclic ring group;
R 2 is a substituent group;
n is 1–5; and
provided that the R 2 groups, their location and n value on one ring are the same as those on the second ring.
10. The device of claim 7 comprising a further light-emitting compound to provide a white light emission.
11. The device of claim 10 further comprising a blue light-emitting compound to provide a white light emission.
12. The device of claim 10 further comprising a filter over-lying the device.
13. The device of claim 9 wherein W represents the atoms to complete a cyclohexane ring.
14. The device of claim 9 wherein W represents the atoms to complete an adamantane ring.
15. The device of claim 7 wherein R 2 is located in meta or para positions of the phenyl groups.
16. The device of claim 7 wherein R 2 are independently selected from the group consisting of fluorine, fluorine containing groups, alkyl, aryl, alkoxy and aryloxy groups.
17. The device of claim 7 wherein R 2 is phenyl.
18. The device of claim 7 wherein R 2 is fluorine.
19. The device of claim 7 wherein R 2 is a fluorine-containing group.
20. The device of claim 7 wherein R 2 is selected from the group consisting of trifluoromethyl, pentafluoroethyl and fluorinated-phenyl groups.
21. The device of claim 7 wherein R 3 , R 4 or R 5 is selected from the group consisting of trifluoromethyl, pentafluoroethyl and fluorinated-phenyl groups.
22. The device of claim 1 wherein the host is an amine compound.
23. The device of claim 1 wherein the host comprises N,N′-di-1-naphthalenyl-N,N′-diphenyl-4,4′-diaminobiphenyl.
24. The device of claim 7 wherein the substituents are selected to provide a reduced loss of initial luminance compared to a device containing no compound of Formula (II).
25. The device of claim 7 wherein the layer comprises a host and dopant where the dopant is present in an amount of up to 10%-wt of the host.
26. The device of claim 25 wherein the dopant is present in an amount of 0.1–5.0%-wt of the host.
27. The device of claim 1 wherein the rubrene compound is selected from the following:
28. A light-emitting device containing the OLED device of claim 1 .
29. A light-emitting display containing the OLED device of claim 1 .
30. A method of emitting light comprising subjecting the device of claim 1 to an applied voltage.
31. An OLED device of claim 1 wherein the rubrene derivative has a wavelength of maximum emission (λ max ) in ethyl acetate solution such that 565 nm<λ max ≦625nm.